Cylinder attaching means



July 18, 1944; v. I. MONCRIEFF 2,353,779

CYLINDER ATTACHING. MEANS Filed Oct. 9, 1941 2 sheets-sheet'l INVENTORIVeon I. Mon crzef? y mM ATTORNEY y 1944. 'v. L'MONCRIEFF 2,353,779

7 I CYLINDER ATTACHING MEANS Filed 001:. 9, 1941 2 Sheets-Sheet '2INVENTOR VeonLMoncrze-ff ATTORNEY.

Patented July 18, 1944 2,353,779 CYLINDER AT'IACHIN G MEANS Veon I.Moncriefl, West Hartford, Conn., assignor to United Aircraft orporation,East Hart- 7 ford, Conn., a corporation of Delaware Application October9, 1941, Serial No. 414,319 Claims. (01. 123-171) This invention relatesto improvements in internal-combustion engines and has particularreference to an improved arrangement for secur ing the cylinders of suchan engine to the engine crankcase.

An object of the invention resides in the provision of an improvedsecuring means for an internal-combustion engine cylinder whichwillpermitmore effective cooling of the cylinder and particularly of theinner or barrel portion of the cylinder.

A further object resides in the provision improved means for securingthe cylinders of an air-cooled internal-combustion engine to the en}gine crankcase which will permit the extension of the finned area of thecylinder barrel approximately to the inner or crankcase end of cylinder.V

A still further object resides in the provision of improved means forsecuring the cylinders of the a radial type of internal-combustionengine to the engine crankcase which will relieve the bar; rel portionsof the cylinders from the stresses due to explosion forces in the outerends of the cylinders and thereby permit the cylinder barrel pontions tobe made with a thinner wall section or to be made of a material ofsomewhat less structural strength than that ordinarily employed but withimproved heat conducting characteristics."

Other objects andadvantages will be more particularly pointed outhereinafter or will become apparent as the description proceeds.

In the accompanying drawings, in which like reference numerals are usedto designate similar parts throughout, there is illustrated, in twoslightly modified forms, a suitable mechanical embodiment for thepurpose of disclosing thei'n vention. The drawings, however, are for thepure pose of illustration only and are not to be taken as limiting orrestricting the invention sinceit will be apparent to those skilled inthe art that various changes in the illustrated embodiments may beresorted to without in any way exceed j ing the scope of the invention.7

In the drawings,

Fig. 1 is a longitudinal sectional view through an engine cylinder and afragmentary portionof the engine crankcase showing means constructedaccording to the invention for attaching the cylinder to the crankcase,the section being taken on the line ll of Fig. 2.

Fig. 2 is a transverse sectional view taken ,on the line 22 of Fig. 1and showing a complete sectional view of one cylinder and the supportingmeans therefor and sectional views of fragmentary portions of adjacentcylinders and their sup-- engine cylinder secured to the enginecrankcase by the improved cylinder attaching means.

Referring to the drawings in detail, and particularly to Fig. 1, thenumeral It generally indicates the engine crankcase. This crankcase maybe generally cylindrical in the case of a radial type of engine and mayhave a cylinder supporting portion separated by internal web members, asindicated at I2 and M, from chambers, as indicated at It and I8 locatedone at each side of the cylinder carrying portion. While an arrangementparticularly adapted to an air-cooled radial type of internal-combustionengine has been particularly illustrated for the purpose of disclosingthe invention, it is to be understood that this invention is not limitedto any particular type of internal-combustion engine but may be used inany engine to which its principles advantageously pply.

. The webs l2 and I4 carry a. plurality of annular seats, one of whichis indicated at 20, one for each cylinder, these seats being adapted tocooperate with the crankcase end of thecylinder to locate this end ofthe cylinder relative to the crankcase and hold it firmly in position.

The crankcase also carries a plurality of outwardly extending integralboss members concentric with the seats 20, one of which is indicated at22, growing out of the crankcase in substantial alignment with theperipheries of the internal webs I2 and I4 and provided at their outerends with respective integral reinforcing rings 24. These bosses extendout from the crankcase a distancesuch that when a cylinder is mounted inposition on the seat 20 the rings 24 will overlie the inner ends of therespective cylinder heads.

Thecylinders, one of which is generally indicated at 26, each comprisesa head portion 28 and a barrel portion 30. In the case of an aircooledengine both of these cylinder portions are provided with external heatdissipating fins, as

indicated at 32 for the head portion and 34 for position as shown inFig. 3.

Near its inner end the barrel portion of the engine cylinder is providedwith an external shoulder 36 which compresses a resilient packing member38 between itself and an internal shoulder 4%! provided in the cylinderbarrel seat 20. The internal diameter of the ring member 24 issufficiently large so that the finned barrel portion 30 of the cylindercan be passed therethrough. In securing the cylinder to the crankcasethe barrel portion is passed through the ring 24 until the threads inthe ring and on the head portion can be engaged. The cylinder is thenturned down upon the screw threads until the proper position of thecylinder relative to the crankcase is obtained. In this position thepack-- 'ing member 38 will be compressed between the shoulders 36 and 40to provide an oil seal between the inner end of the cylinder and thecrankcase. Preferably the boss 22 is split, as indicated by the lines 42and 44 on Fig. 2, and apertured to receive clamp bolts, indicated at 46and 48 in Fig. 2 and 4S and 50 in Fig. 1. With this 'a'r-' r'angementthe clamp bolts may be loosened before the cylinder is turned into placeand" may be tightened after the cylinder is 'put in its proper operativeposition relative to the crankcase to firmly secure the cylinder'in thisposition against forces tending to move it, such as engine vibration andvalve loads, and to keep the cylinder head from becoming loose in thering 24 due to expansive changes of the ring and the cylinder head underthe influence of varying cylinder head temperatures.

In the formof the invention shown in Fig. 1

the head portion 28 and the barrel portion '30 are shown as a singleunitary structure and this structure may, if desired, be formed of somesuitable light weight material such as an aluminum alloy, since thestresses due to explosive forces in the cylinder are not transmittedthrough the relatively thin barrel portion but'are transmitted throughthe heavy head portion directly to the ring 24 of the cylinder securingboss. At the same time the wall of the barrel portion can be maderelatively thin so that heat willbe rapidly conducted through this wallto the barrel fins 34 which may be formed by machining away a por tionof the original barrel blank or may be formed separately and attached tothe barrel by some means known to the art. By thus providing a thinwalled barrel of a material of excellent heat conducting properties,such as an aluminum alloy, and extending the heat dissipating finssubstantially to the bottom or inner end of the barrel, the cooling 'ofthe barrel is materially improved. Also, because the boss 22 can be maderelatively rigid and the cylinder head' 28 is'also relatively rigid,movement of the outer end of the cylinder relative to the crankcase willbe materially reduced thereby giving an improved valve operation byeliminating from the valve gear the clearances due to the heat expansionof the cylinder barrel and movements due to the flexibility of thisbarrel under operating loads. Additionally, the cylinder attachingbosses may be made to serve as bafiles for guidingthe cooling air aroundthe cylinder barrels.

As is particularly shown in Fig. 2, each boss is provided with a pair ofdiametrically opposed openings, as indicated at 52 and 54 one of whichprovides an entrance opening and the other of which providesan exitopening for the cooling air for the cylinder barrel. As is particularlyshown in Fig. 1, these openings are extended downwardly to the outersurface of the cylinder barrel seat 20 so that the cooling air entranceand exit openings both extend over the entire length of the finned areaof the cylinder barrel to insure the admission of the cooling air to allof the barrel fins. The portions of the boss on each side of the airentrance and exit openings are positioned substantially in contact withthe peripheries of the barrel fins so that the cooling air is forced toflow through the spaces between the fins and a reasonably uniformdistribution of cooling air over the entire length of the cyl inderbarrel is obtained. The portions of the bosses between the adjacentcylinders block the flow of cooling air at these locations so that allis. forced to flow through the finned area of the various cylinderbarrels.

"'Ihe'arrangement illustrated in Fig. 3 shows that the improved cylinderattaching meansis also adaptable to the attachment of acompositccylinder to the engine crankcase. In this arrangement the cylinderbarrel 56 may be formed separately from the head 58 and may, if desired,beformed of a different material. For example, the barrel 56 may be madeof steel while the head 58 may be made of. a suitable aluminum alloy.The cylinder head in the illustrated arrangement, is provided near itsopen end with external screw threads which engage withthe internal screwthreads in the ring 24 of the boss 22 andwith internal screw threadswhich engage with external threads formed on the barrel 5%,. to securethe barrel in operative position relative to the head 58 and the enginecrankcase. In other respects the form of. the invention shown in Fig. 3is substantially the same as that shown in Fig. 1 and described above.In the arrangement shown in Fig. 3 the barrel fins 60 extend forsubstantially the entire length of the cylinder barrel 56 between thehead 58 and. the barrel seat 20 and cooling air is forced-t0 flowbetween all of these fins by the openings 52 and 54 which extend overthe entire length of the finned area of.

the cylinder barrel. The barrel 56 is also provided near its inner orcrankcase end with an the cylinder and the crankcase.

While a suitable mechanical embodiment has been illustrated in theaccompanying drawings in. two slightly modified forms and has beenhereinabove described for the purpose of disclosing the invention, it isto be understood that the invention is not limited to the particularem-- bodiments so illustrated and described but that such changes in thesize, shape and arrangements of the various parts may be resorted to ascome within the scope of the sub-joined claims.

Having now described the invention so that others skilled in the art mayclearly understand the same, what it is desired to secure by LettersPatent is as follows:

case, a guide seat surrounding an aperture in the bottom of saiddepression and engaging the in ner end of said barrel portion, and meanson said head portion engaging said boss at its outer end,

said barrel fins extending over substantially the entire length of saidbarrel.

2. In an engine having a crankcase and a cylinder comprising a finnedhead portion and a finned barrel portion, means for securing saidcylinder to said crankcase, comprising, a diametrically split bossextending outwardly from said crankcase surrounding the barrel portionof said cylinder outside of the barrel fins and engaging with the headportion thereof, said boss having at its outer end an internallythreaded reinforcing ring engaging with external threads on the adjacentend of said cylinder head and having openings therein providing acooling air passage between said barrel portion and said boss from saidcrankcase to said reinforcing ring, and clamp bolts extending throughthe two parts of said split boss for contracting said reinforcing ringupon the threaded portion of said cylinder head.

3. In an engine having a crankcase provided with an aperture and adepression surrounding said aperture and a cylinder comprising a finnedhead portion and a finned barrel portion, means for securing saidcylinder to said crankcase, comprising, a seat for the crankcase end ofsaid barrel portion surrounding said crankcase aperture, a boss integralwith said crankcase surrounding said depression and extending outwardlyfrom said crankcase to overlap the barrel portion of said cylinder andengage with th head portion thereof, a cylinder portion between saidhead fins and said barrel fins engageable with the outer end of saidboss to secure said cylinder in operative position on said crankcase,said boss having air passage openings at opposite sides thereofextending substantially from the outer end of said boss to the bottom ofsaid depression to provide a flow of cooling air over substantially theentire length of said cylinder barrel.

e. In an air-cooled engine having a crankcase and a separate cylindercomprising an exteriorly finned head portion and an exteriorly finnedbarrel portion in which the finned area of said barrel portion extendsfrom said head portion substantially to the crankcase end of said barrelportion, means for securing said cylinder to said crankcase, comprising,a seat carried by said crankcase for receiving the crankcase end of saidcylinder barrel portion, said barrel when in operative positionterminating substantially flush with the inner side of said seat, and aboss integral with said crankcase surrounding said seat and extendingoutwardly from said crankcase to overlap said barrel portion and engagewith the head portion of said cylinder and hold the head and cylinder inoperative position on said crankcase, said boss having an openingtherein at the one side of said cylinder barrel portion and an openingtherein at the opposite side of said cylinder barrel portion, saidopenings extending th entire length of the finned area of said cylinderbarrel portion.

5. In an engine having a crankcase and a plurality of separateair-cooled cylinders each comprising an exteriorly finned head portionand an exteriorly finned barrel portion, with the barrel portion finsextending from the head portion substantially to the crankcase end ofthe barrel portion, means for securing said cylinders to said crankcase,comprising a boss for each cylinder extending outwardly from andintegral with said crankcase surrounding the barrel portions of therespective cylinders and engaged with the head portions thereof to holdthe head and cylinder in operative position on said crankcase, openingsin said bosses at the front and rear sides of said cylinders to admitcooling air to said cylinder barrels, and means interconnecting saidbosses between said cylinders to constitute air battles to direct saidcooling air through said openings.

6. In combination, an engine crankcase, a separate engine cylinderbarrel and head assembly mounted on said crankcase, air directingbaflles arranged around said cylinder barrel, integral with saidcrankcase and removably secured to said barrel and head assemblyadjacent said head, and acting as the main support for retaining saidbarrel on said crankcase.

7. In an engine, a crankcase, a cylinder supporting column connected atits inner end to said crankcase and extending outwardly therefrom, anopening in said crankcase inside of said column, a unitary enginecylinder assembly having a head portion and a barrel portion, meansattaching said head portion of said assembly to the outer end of saidcolumn, said barrel portion of said assembly extending through saidcolumn and having an end received in said crankcase opening, said columnhaving an opening therein for passing a cooling fluid over said barrelportion.

8. A unity air-cooled engine cylinder assembly comprising, incombination, a relatively thick finned head portion, a relatively thinfinned barrel portion, and means for attaching said assembly to anengine crankcase having an extension thereon, said attaching meanscomprising means carried by said head portion and positioned betweensaid finned barrel portion and said finned head portion for attachmentto the outer end of said extension.

9. An air-cooled engine cylinder assembly comprising, in combination, afinned head, a finned barrel, a crankcase having an annular seatreceiving one end of said barrel, the other end of said barrel beingconnected with said head, and supporting means connected to said headand to said crankcase for rigidly supporting said head, independently ofsaid barrel, by said crankcase.

10. In an air-cooled aircraft engine, a crankcase, and annular seat insaid crankcase, a finned barrel having one end thereof guided by saidseat, a finned head secured to the other end of said barrel, and a wallmember connected to both said head and said crankcase for supportingsaid head by said crankcase, said wall member being spaced from saidbarrel to form therewith an air duct for directing cooling air over saidbarrel fins.

VEON I, MONCRIEFF.

